peterswim:
I've done the research, I've talked to many people and I've done a test ride and I'm all set to purchase a Surly LHT. I've looked at the measurements, I've measured myself and my current bikes and everything suggests I need a 59cm frame, but the LHT only comes in even sizes. So, am I better going slightly smaller (58cm) or slightly bigger (60cm)? I'm sure it won't make an iota of difference and I'll be happy with whatever I choose, but I know there are knowledgeable folks out there who may be be able to guide me in a way I have not considered. Thanks for any input and happy riding.

John Nelson:
Is there any way you could test ride each? I realize that this is a tall order because finding a bike shop with one of each on the floor might be very difficult.

Another possibility is to talk with the bike shop you intend to order through. See if they'll agree to order one and let you test ride it. If it feels like the other size might be better, ask if they can then order the other one. The bike shop I deal with would do that.

Note that adjustments in seat height, saddle setback, stem length, etc. can fine tune the fit, and any good bike shop would be willing to make those adjustments for you.

dkoloko:
Frankly, I think bicyclists get too hung up on touring bike sizes. Difference between 59cm and 58cm, 3/8 inch; you might alter the bike's height that much by difference in tire size. My Cannondale touring bike only came in four sizes, and they couldn't sell enough to keep selling touring bikes, even in just those few sizes. As far as test riding first, so often recommended, not where I live. Rarely a touring bike on the sales floor, and lots of luck being my size. A knowledgeable bike shop person will know the bike and size you up, with an eye to how your proportions mesh with the other bike parameters beside bike height. That said, I think you'll do fine, with either the 58cm or 60cm bike, after adjustments such as raising or lowering the saddle, tilting handlebars, etc. In fact, I think you'll get more out of fine tuning the various adjustments to size, then you'll get from choosing between the 58cm or 60cm bike.

DaveB:
Assuming the standover height allows you to comfortably straddle the 60 cm frame (if not, don't consider it) then the deciding factor can be the top tube length. If you have long arms and/or prefer a more stretched out riding position, get the 60. If you want a more upright position, the shorter top tube of the 58 will make this easier. In either case, stem length and angle can be chosen to get a comfortable riding position but the proper frame choice makes it a bit easier.

e46rick:
Be sure to compare top tube lengths as well as frame size.

For me, it's always been a bit easier to adjust my fit to a slightly smaller frame rather than to a slightly larger one. Stem length, rise, stack height and seat post (up-down, fore-aft) are easier to adjust on a smaller versus larger frame IMO.